summaryrefslogtreecommitdiffstats
path: root/drivers/watchdog/wm831x_wdt.c
blob: 871caea4e1c62d7a868cfb24593d1de7c1f244c2 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
/*
 * Watchdog driver for the wm831x PMICs
 *
 * Copyright (C) 2009 Wolfson Microelectronics
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation
 */

#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/miscdevice.h>
#include <linux/platform_device.h>
#include <linux/watchdog.h>
#include <linux/uaccess.h>
#include <linux/gpio.h>

#include <linux/mfd/wm831x/core.h>
#include <linux/mfd/wm831x/pdata.h>
#include <linux/mfd/wm831x/watchdog.h>

static int nowayout = WATCHDOG_NOWAYOUT;
module_param(nowayout, int, 0);
MODULE_PARM_DESC(nowayout,
		 "Watchdog cannot be stopped once started (default="
		 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");

static unsigned long wm831x_wdt_users;
static struct miscdevice wm831x_wdt_miscdev;
static int wm831x_wdt_expect_close;
static DEFINE_MUTEX(wdt_mutex);
static struct wm831x *wm831x;
static unsigned int update_gpio;
static unsigned int update_state;

/* We can't use the sub-second values here but they're included
 * for completeness.  */
static struct {
	int time;  /* Seconds */
	u16 val;   /* WDOG_TO value */
} wm831x_wdt_cfgs[] = {
	{  1, 2 },
	{  2, 3 },
	{  4, 4 },
	{  8, 5 },
	{ 16, 6 },
	{ 32, 7 },
	{ 33, 7 },  /* Actually 32.768s so include both, others round down */
};

static int wm831x_wdt_set_timeout(struct wm831x *wm831x, u16 value)
{
	int ret;

	mutex_lock(&wdt_mutex);

	ret = wm831x_reg_unlock(wm831x);
	if (ret == 0) {
		ret = wm831x_set_bits(wm831x, WM831X_WATCHDOG,
				      WM831X_WDOG_TO_MASK, value);
		wm831x_reg_lock(wm831x);
	} else {
		dev_err(wm831x->dev, "Failed to unlock security key: %d\n",
			ret);
	}

	mutex_unlock(&wdt_mutex);

	return ret;
}

static int wm831x_wdt_start(struct wm831x *wm831x)
{
	int ret;

	mutex_lock(&wdt_mutex);

	ret = wm831x_reg_unlock(wm831x);
	if (ret == 0) {
		ret = wm831x_set_bits(wm831x, WM831X_WATCHDOG,
				      WM831X_WDOG_ENA, WM831X_WDOG_ENA);
		wm831x_reg_lock(wm831x);
	} else {
		dev_err(wm831x->dev, "Failed to unlock security key: %d\n",
			ret);
	}

	mutex_unlock(&wdt_mutex);

	return ret;
}

static int wm831x_wdt_stop(struct wm831x *wm831x)
{
	int ret;

	mutex_lock(&wdt_mutex);

	ret = wm831x_reg_unlock(wm831x);
	if (ret == 0) {
		ret = wm831x_set_bits(wm831x, WM831X_WATCHDOG,
				      WM831X_WDOG_ENA, 0);
		wm831x_reg_lock(wm831x);
	} else {
		dev_err(wm831x->dev, "Failed to unlock security key: %d\n",
			ret);
	}

	mutex_unlock(&wdt_mutex);

	return ret;
}

static int wm831x_wdt_kick(struct wm831x *wm831x)
{
	int ret;
	u16 reg;

	mutex_lock(&wdt_mutex);

	if (update_gpio) {
		gpio_set_value_cansleep(update_gpio, update_state);
		update_state = !update_state;
		ret = 0;
		goto out;
	}


	reg = wm831x_reg_read(wm831x, WM831X_WATCHDOG);

	if (!(reg & WM831X_WDOG_RST_SRC)) {
		dev_err(wm831x->dev, "Hardware watchdog update unsupported\n");
		ret = -EINVAL;
		goto out;
	}

	reg |= WM831X_WDOG_RESET;

	ret = wm831x_reg_unlock(wm831x);
	if (ret == 0) {
		ret = wm831x_reg_write(wm831x, WM831X_WATCHDOG, reg);
		wm831x_reg_lock(wm831x);
	} else {
		dev_err(wm831x->dev, "Failed to unlock security key: %d\n",
			ret);
	}

out:
	mutex_unlock(&wdt_mutex);

	return ret;
}

static int wm831x_wdt_open(struct inode *inode, struct file *file)
{
	int ret;

	if (!wm831x)
		return -ENODEV;

	if (test_and_set_bit(0, &wm831x_wdt_users))
		return -EBUSY;

	ret = wm831x_wdt_start(wm831x);
	if (ret != 0)
		return ret;

	return nonseekable_open(inode, file);
}

static int wm831x_wdt_release(struct inode *inode, struct file *file)
{
	if (wm831x_wdt_expect_close)
		wm831x_wdt_stop(wm831x);
	else {
		dev_warn(wm831x->dev, "Watchdog device closed uncleanly\n");
		wm831x_wdt_kick(wm831x);
	}

	clear_bit(0, &wm831x_wdt_users);

	return 0;
}

static ssize_t wm831x_wdt_write(struct file *file,
				const char __user *data, size_t count,
				loff_t *ppos)
{
	size_t i;

	if (count) {
		wm831x_wdt_kick(wm831x);

		if (!nowayout) {
			/* In case it was set long ago */
			wm831x_wdt_expect_close = 0;

			/* scan to see whether or not we got the magic
			   character */
			for (i = 0; i != count; i++) {
				char c;
				if (get_user(c, data + i))
					return -EFAULT;
				if (c == 'V')
					wm831x_wdt_expect_close = 42;
			}
		}
	}
	return count;
}

static const struct watchdog_info ident = {
	.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
	.identity = "WM831x Watchdog",
};

static long wm831x_wdt_ioctl(struct file *file, unsigned int cmd,
			     unsigned long arg)
{
	int ret = -ENOTTY, time, i;
	void __user *argp = (void __user *)arg;
	int __user *p = argp;
	u16 reg;

	switch (cmd) {
	case WDIOC_GETSUPPORT:
		ret = copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
		break;

	case WDIOC_GETSTATUS:
	case WDIOC_GETBOOTSTATUS:
		ret = put_user(0, p);
		break;

	case WDIOC_SETOPTIONS:
	{
		int options;

		if (get_user(options, p))
			return -EFAULT;

		ret = -EINVAL;

		/* Setting both simultaneously means at least one must fail */
		if (options == WDIOS_DISABLECARD)
			ret = wm831x_wdt_start(wm831x);

		if (options == WDIOS_ENABLECARD)
			ret = wm831x_wdt_stop(wm831x);
		break;
	}

	case WDIOC_KEEPALIVE:
		ret = wm831x_wdt_kick(wm831x);
		break;

	case WDIOC_SETTIMEOUT:
		ret = get_user(time, p);
		if (ret)
			break;

		if (time == 0) {
			if (nowayout)
				ret = -EINVAL;
			else
				wm831x_wdt_stop(wm831x);
			break;
		}

		for (i = 0; i < ARRAY_SIZE(wm831x_wdt_cfgs); i++)
			if (wm831x_wdt_cfgs[i].time == time)
				break;
		if (i == ARRAY_SIZE(wm831x_wdt_cfgs))
			ret = -EINVAL;
		else
			ret = wm831x_wdt_set_timeout(wm831x,
						     wm831x_wdt_cfgs[i].val);
		break;

	case WDIOC_GETTIMEOUT:
		reg = wm831x_reg_read(wm831x, WM831X_WATCHDOG);
		reg &= WM831X_WDOG_TO_MASK;
		for (i = 0; i < ARRAY_SIZE(wm831x_wdt_cfgs); i++)
			if (wm831x_wdt_cfgs[i].val == reg)
				break;
		if (i == ARRAY_SIZE(wm831x_wdt_cfgs)) {
			dev_warn(wm831x->dev,
				 "Unknown watchdog configuration: %x\n", reg);
			ret = -EINVAL;
		} else
			ret = put_user(wm831x_wdt_cfgs[i].time, p);

	}

	return ret;
}

static const struct file_operations wm831x_wdt_fops = {
	.owner = THIS_MODULE,
	.llseek = no_llseek,
	.write = wm831x_wdt_write,
	.unlocked_ioctl = wm831x_wdt_ioctl,
	.open = wm831x_wdt_open,
	.release = wm831x_wdt_release,
};

static struct miscdevice wm831x_wdt_miscdev = {
	.minor = WATCHDOG_MINOR,
	.name = "watchdog",
	.fops = &wm831x_wdt_fops,
};

static int __devinit wm831x_wdt_probe(struct platform_device *pdev)
{
	struct wm831x_pdata *chip_pdata;
	struct wm831x_watchdog_pdata *pdata;
	int reg, ret;

	if (wm831x) {
		dev_err(&pdev->dev, "wm831x watchdog already registered\n");
		return -EBUSY;
	}

	wm831x = dev_get_drvdata(pdev->dev.parent);

	ret = wm831x_reg_read(wm831x, WM831X_WATCHDOG);
	if (ret < 0) {
		dev_err(wm831x->dev, "Failed to read watchdog status: %d\n",
			ret);
		goto err;
	}
	reg = ret;

	if (reg & WM831X_WDOG_DEBUG)
		dev_warn(wm831x->dev, "Watchdog is paused\n");

	/* Apply any configuration */
	if (pdev->dev.parent->platform_data) {
		chip_pdata = pdev->dev.parent->platform_data;
		pdata = chip_pdata->watchdog;
	} else {
		pdata = NULL;
	}

	if (pdata) {
		reg &= ~(WM831X_WDOG_SECACT_MASK | WM831X_WDOG_PRIMACT_MASK |
			 WM831X_WDOG_RST_SRC);

		reg |= pdata->primary << WM831X_WDOG_PRIMACT_SHIFT;
		reg |= pdata->secondary << WM831X_WDOG_SECACT_SHIFT;
		reg |= pdata->software << WM831X_WDOG_RST_SRC_SHIFT;

		if (pdata->update_gpio) {
			ret = gpio_request(pdata->update_gpio,
					   "Watchdog update");
			if (ret < 0) {
				dev_err(wm831x->dev,
					"Failed to request update GPIO: %d\n",
					ret);
				goto err;
			}

			ret = gpio_direction_output(pdata->update_gpio, 0);
			if (ret != 0) {
				dev_err(wm831x->dev,
					"gpio_direction_output returned: %d\n",
					ret);
				goto err_gpio;
			}

			update_gpio = pdata->update_gpio;

			/* Make sure the watchdog takes hardware updates */
			reg |= WM831X_WDOG_RST_SRC;
		}

		ret = wm831x_reg_unlock(wm831x);
		if (ret == 0) {
			ret = wm831x_reg_write(wm831x, WM831X_WATCHDOG, reg);
			wm831x_reg_lock(wm831x);
		} else {
			dev_err(wm831x->dev,
				"Failed to unlock security key: %d\n", ret);
			goto err_gpio;
		}
	}

	wm831x_wdt_miscdev.parent = &pdev->dev;

	ret = misc_register(&wm831x_wdt_miscdev);
	if (ret != 0) {
		dev_err(wm831x->dev, "Failed to register miscdev: %d\n", ret);
		goto err_gpio;
	}

	return 0;

err_gpio:
	if (update_gpio) {
		gpio_free(update_gpio);
		update_gpio = 0;
	}
err:
	return ret;
}

static int __devexit wm831x_wdt_remove(struct platform_device *pdev)
{
	if (update_gpio) {
		gpio_free(update_gpio);
		update_gpio = 0;
	}

	misc_deregister(&wm831x_wdt_miscdev);

	return 0;
}

static struct platform_driver wm831x_wdt_driver = {
	.probe = wm831x_wdt_probe,
	.remove = __devexit_p(wm831x_wdt_remove),
	.driver = {
		.name = "wm831x-watchdog",
	},
};

static int __init wm831x_wdt_init(void)
{
	return platform_driver_register(&wm831x_wdt_driver);
}
module_init(wm831x_wdt_init);

static void __exit wm831x_wdt_exit(void)
{
	platform_driver_unregister(&wm831x_wdt_driver);
}
module_exit(wm831x_wdt_exit);

MODULE_AUTHOR("Mark Brown");
MODULE_DESCRIPTION("WM831x Watchdog");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:wm831x-watchdog");